Microfracture apparatuses and methods

ABSTRACT

Apparatuses and methods for microfracture (e.g., forming a plurality of microfractures in a bone to encourage cartilage regeneration). Some of the present apparatuses and methods are configured to create microfractures with smaller transverse dimensions (e.g., diameters) and greater depths than previously known. Some of the present apparatuses and methods comprise a penetrator removal tab coupled to the penetrator and configured to retract the penetrator relative to the cannula.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/878,173, filed Oct. 8, 2015, which is a divisional of U.S.application Ser. No. 13/788,713, filed Mar. 7, 2013, which claimspriority to U.S. Provisional Patent Application No. 61/609,053, filedMar. 9, 2012; 61/665,084, filed Jun. 27, 2012; 61/720,778, filed Oct.31, 2012; 61/736,913, filed Dec. 13, 2012; and 61/755,783, filed Jan.23, 2013; all of which are incorporated by reference in theirentireties.

BACKGROUND 1. Field of the Invention

The present invention relates generally to orthopedic treatments, moreparticularly, but not by way of limitation, to devices and methods forcreating microfractures (e.g., in subchondral bone).

2. Description of Related Art

Examples of treatment methods and apparatuses for creatingmicrofractures in bone are disclosed in (1) J. P. Benthien, et al., Thetreatment of chondral and osteochondral defects of the knee withautologous matrix-induced chondrogenesis (AMIC): method description andrecent developments, Knee Surg Sports Traumatol Arthrosc, August 2011,19(8):1316-1319; (2) Thomas J. Gill, M D, et al., The Treatment ofArticular Cartilage Defects Using the Microfracture Technique, Journalof Orthopaedic & Sports Physical Therapy, October 2006, 36(10):728-738;(3) L. de Girolamo, Treatment of chondral defects of the knee with onestep matrix-assisted technique enhanced by autologous concentrated bonemarrow: In vitro characterisation of mesenchymal stem cells from iliaccrest and subchondral bone, Injury, Int. J. Care Injured 41 (2010)1172-1177; (4) Pub. No. US 2009/0143782; (5) Pub. No. US 2005/0043738;(6) Pub. No. US 2005/0021067; and (7) Pub. No. US 2004/0147932.

SUMMARY

This disclosure includes embodiments of apparatuses, kits, and methodsfor creating microfractures in bone (e.g., subchondral bone). At leastsome of the present embodiments are configured to create a microfracturewith a greater depth-to-width ratio than has been possible with knownmethods and apparatuses. For example, some embodiments are configured tocreate a microfracture in subchondral bone having a (e.g., first)transverse dimension (e.g., diameter) of less than 1.2 millimeters (mm)(e.g., between 1 mm and 1.1 mm, less than 1.1 mm, less than 1.05 mm,less than 1 mm), and a depth (or length) of at least 5 mm (e.g., 7 mm, 8mm, 8-10 mm, or the like).

Some embodiments of the present apparatuses comprise: a cannula having afirst end, a second end, and a channel extending between the first endand the second end, the cannula having a primary portion and a distalportion between the primary portion and the second end, the distalportion configured such that a second end of the channel is disposed atan angle relative to a first end of the channel (e.g., with the distalportion disposed at an angle relative to the primary portion); and apenetrator having an enlarged head, a pointed distal end, and a (e.g.,first) transverse dimension of less than 1.2 millimeters (mm) (e.g.,between 1 mm and 1.1 mm, less than 1.1 mm, less than 1.05 mm, less than1 mm), the penetrator configured to be disposed in the channel of thecannula such that the penetrator is movable between a retracted positionand an extended position in which the distal end extends beyond thesecond end of the cannula by a penetration distance of at least 5 mmthat is limited by the enlarged head contacting the cannula; where thepenetrator is configured to be moved from the retracted position to theextended position substantially without rotation of the penetrator toform in subchondral bone a microfracture having a depth of at least 5mm. In some embodiments, the penetrator comprises an elongated body andan enlarged head coupled to the elongated body. In some embodiments, theenlarged head is unitary with the elongated body.

Some embodiments of the present apparatuses comprise: a cannula having afirst end, a second end, and a channel extending between the first endand the second end; and a penetrator having a distal end and a (e.g.,first) transverse dimension of less than 1.2 millimeters (mm) (e.g.,between 1 mm and 1.1 mm, less than 1.1 mm, less than 1.05 mm, less than1 mm), the penetrator configured to be disposed in the channel of thecannula such that the penetrator is movable between a retracted positionand an extended position in which the distal end extends beyond thesecond end of the cannula by a penetration distance of at least 5 mm;where the penetrator is configured to be moved from the retractedposition to the extended position substantially without rotation of thepenetrator to form in subchondral bone a microfracture having a depth ofat least 5 mm.

Some embodiments of the present apparatuses comprise: a cannula having afirst end, a second end, and a channel extending between the first endand the second end; and a penetrator having a distal end and atransverse dimension, the penetrator configured to be disposed in thechannel of the cannula such that the penetrator is movable between aretracted position and an extended position in which the distal endextends beyond the second end of the cannula by a penetration distancethat is at least 5 times greater than the transverse dimension of thepenetrator; where the penetrator is configured to be moved from theretracted position to the extended position substantially withoutrotation of the penetrator to form in subchondral bone a microfracturehaving a depth that is at least 5 times greater than the transversedimension of the penetrator. In some embodiments, the transversedimension of the penetrator is less than 1.2 millimeters (mm) (e.g.,between 1 mm and 1.1 mm, less than 1.1 mm, less than 1.05 mm, less than1 mm).

In some embodiments, the cannula has a primary portion and a distalportion between the primary portion and the second end, the distalportion configured such that a second end of the channel is disposed atan angle relative to a first end of the channel. In some embodiments,the transverse dimension of the penetrator is less than 1.1 millimeters(mm). In some embodiments of the present apparatuses, the penetrator isconfigured to be manually moved from the retracted position to theextended position. In some embodiments, the penetrator has an enlargedhead, and the penetration distance is limited by the enlarged headcontacting the cannula. In some embodiments, the penetrator comprises anelongated body and an enlarged head coupled to the elongated body. Insome embodiments, the enlarged head is unitary with the elongated body.In some embodiments, the cannula includes a recessed portion and ashelf, the recessed portion extending from the first end of the cannulatoward the second end of the cannula, the shelf disposed between therecessed portion and the second end of the cannula such that thepenetration distance is limited by the enlarged head contacting theshelf. In some embodiments, the recessed portion has a depth that is atleast as large as the penetration distance. In some embodiments, theenlarged head has a cylindrical shape with a length and a transversedimension that is smaller than the length. In some embodiments, theenlarged head has a transverse dimension that is at least 90% of acorresponding transverse dimension of the recessed portion. In someembodiments, the distal end of the penetrator is pointed. In someembodiments, the penetrator comprises at least one of a biocompatiblemetal, nickel-titanium alloy, stainless steel, and 316L stainless steel.In some embodiments, a coating is disposed on at least the penetrationportion of the penetrator. In some embodiments, the coating ishydrophilic. In some embodiments, the coating comprises silver ions. Insome embodiments, the penetrator includes a primary portion and apenetration portion, the primary portion having a circularcross-section, the penetration portion disposed between the primaryportion and the distal end, the penetration portion having a circularcross-section that is smaller than the circular cross-section of theprimary portion.

In some embodiments of the present apparatuses, the first transversedimension is in the penetration portion, and a second transversedimension smaller than the first dimension is between the firsttransverse dimension and the primary portion. In some embodiments, thepenetration portion has a length and the second transverse dimension issubstantially constant along part of the length of the penetrationportion. In some embodiments, the penetration portion includes a narrowportion with at least one transverse dimension that is less than anadjacent transverse dimension of the penetration portion, such that thenarrow portion is configured to reduce contact between the penetratorand a bone if the penetration portion is inserted into bone.

In some embodiments of the present apparatuses, the penetrator includesa primary portion and a penetration portion disposed between the primaryportion and the distal end, the first transverse dimension is in thepenetration portion, and a second transverse dimension is between thefirst transverse dimension and the primary portion. In some embodiments,the second transverse dimension is smaller than the first transversedimension. In some embodiments, the penetration portion has a length,and the second transverse dimension is substantially constant along partof the length of the penetration portion. In some embodiments, the firsttransverse dimension is closer to the distal end than to the primaryportion. In some embodiments, the penetrator has a first cross-sectionalarea at the first transverse dimension, the penetrator has a secondcross-sectional area at the second transverse dimension, and the firstcross-sectional area is larger than the second cross-sectional area. Insome embodiments, the penetrator has a first circular cross section atthe first transverse dimension, and the penetrator has a second circularcross section at the second transverse dimension.

In some embodiments of the present apparatuses, the distal end includesa pointed tip with a cross-sectional shape defined by a tip angle of 60degrees or greater. In some embodiments, the tip angle is bisected by acentral longitudinal axis of the penetration portion. In someembodiments, the tip angle is greater than 90 degrees. In someembodiments, the tip angle is greater than 120 degrees (e.g., 180degrees, such that the tip is flat or at a right-angle to thelongitudinal axis of the end of the penetration portion rather thanpointed). In other embodiments, the tip can be rounded. Some embodimentsfurther comprise: a penetrator removal tab coupled to the penetrator andconfigured to retract the penetrator relative to the cannula. In someembodiments, the cannula includes a handle, the penetrator includes aflange, the penetrator removal tab includes an opening that is has atleast one transverse dimension that is smaller than a transversedimension of the flange; and the penetrator removal tab is configured tobe disposed between the handle and the flange with the penetratorextending through the opening. In some embodiments, the penetratorremoval tab includes a protrusion configured to extend toward the secondend of the cannula and contact the handle to act as a fulcrum forpivoting the penetrator removal tab. In some embodiments, the cannulacomprises a handle having an indicator indicative of the position of thedistal portion of the cannula.

Some embodiments of the present kits comprise: any embodiment of thepresent apparatuses, where the penetrator is a first penetrator; and asecond penetrator having a distal end and a transverse dimension of lessthan 1.2 millimeters (mm) (e.g., between 1 mm and 1.1 mm, less than 1.1mm, less than 1.05 mm, less than 1 mm), the second penetrator configuredto be disposed in the channel of the cannula such that the secondpenetrator is movable between a retracted position and an extendedposition in which the distal end of the second penetrator extends beyondthe second end of the cannula by a second penetrator penetrationdistance that is at least 5 mm and different than the penetrationdistance of the first penetrator.

Some embodiments of the present kits comprise: a first penetrator havinga distal end and a transverse dimension of less than 1.2 millimeters(mm) (e.g., between 1 mm and 1.1 mm, less than 1.1 mm, less than 1.05mm, less than 1 mm), the first penetrator configured to be disposed in achannel of a cannula such that the first penetrator is movable between aretracted position and an extended position in which the distal endextends beyond the second end of the cannula by a first penetrationdistance of at least 5 mm; and a package within which the penetrator issealed. Some embodiments further comprise: a second penetrator sealed inthe package, the second penetrator having a distal end and a transversedimension, the second penetrator configured to be disposed in thechannel of the cannula such that the second penetrator is movablebetween a retracted position and an extended position in which thedistal end extends beyond the second end of the cannula by a secondpenetration distance; where at least one of: (i) the transversedimension of the second penetrator is different than the transversedimension of the first penetrator; and (ii) the second penetrationdistance is different than the first penetration distance. Someembodiments further comprise: a cannula having a first end, a secondend, and a channel extending between the first end and the second end,the channel configured to receive the first penetrator. Some embodimentsfurther comprise: a (e.g., reusable) tray within which the cannula isdisposed.

Some embodiments of the present kits comprise: a cannula having a firstend, a second end, and a channel extending between the first end and thesecond end, the cannula having a primary portion and a distal portionbetween the primary portion and the second end, the distal portiondisposed at an angle relative to the primary portion, the cannulacomprising metal; a re-usable, sterilizable tray; and a package withinwhich the cannula and tray are sealed.

Some embodiments of the present methods (e.g., of forming amicrofracture in subchondral bone of a patient) comprise: disposing amicrofracture apparatus adjacent to the subchondral bone (themicrofracture apparatus comprising: a cannula having a first end, asecond end, and a channel extending between the first end and the secondend; and a penetrator having a distal end and a transverse dimension ofless than 1.2 millimeter (mm) (e.g., between 1 mm and 1.1 mm, less than1.1 mm, less than 1.05 mm, less than 1 mm)); and advancing thepenetrator relative to the cannula, substantially without rotation ofthe penetrator, until the distal end of the penetrator extends into thesubchondral bone to form a microfracture having a depth greater than 5mm. Some embodiments further comprise: repeating the steps of disposingand advancing to form a plurality of microfractures in the subchondralbone. In some embodiments, the apparatus further comprises a penetratorremoval tab coupled to the penetrator and configured to retract thepenetrator relative to the cannula, and the method further comprises:actuating the penetrator removal tab to retract the distal end of thepenetrator from the bone. In some embodiments, the cannula includes ahandle, the penetrator includes a flange, the penetrator removal tabincludes an opening that is has at least one transverse dimension thatis smaller than a transverse dimension of the flange; and the penetratorremoval tab is configured to be disposed between the handle and theflange with the penetrator extending through the opening. In someembodiments, the penetrator removal tab includes a protrusion configuredto extend toward the second end of the cannula and contact the handle toact as a fulcrum for pivoting the penetrator removal tab, and actuatingthe penetrator removal tab includes pivoting the penetrator removal tabaround a point of contact between the protrusion and the handle. In someembodiments, the cannula comprises a handle having an indicatorindicative of the position of the distal portion of the cannula.

In some embodiments, the microfracture apparatus is disposed such thatthe second end of the cannula contacts the subchondral bone.

In some embodiments of the present methods, the penetrator is advancedmanually. In some embodiments, the position of the second end of thecannula relative to the bone is substantially constant while advancingthe penetrator. In some embodiments, the penetrator has an enlargedhead, and the penetration distance is limited by the enlarged headcontacting the cannula. In some embodiments, the cannula includes arecessed portion and a shelf, the recessed portion extending from thefirst end of the cannula toward the second end of the cannula, the shelfdisposed between the recessed portion and the second end of the cannulasuch that the penetration distance is limited by the enlarged headcontacting the shelf. In some embodiments, the recessed portion has adepth that is at least as large as the penetration distance. In someembodiments, the enlarged head has a cylindrical shape with a length anda transverse dimension that is smaller than the length. In someembodiments, the enlarged head has a transverse dimension that is atleast 90% of a corresponding transverse dimension of the recessedportion. In some embodiments, the distal end of the penetrator ispointed. In some embodiments, the penetrator includes a primary portionand a penetration portion, the primary portion having a circularcross-section, the penetration portion disposed between the primaryportion and the distal end, the penetration portion having a circularcross-section that is smaller than the circular cross-section of theprimary portion.

Any embodiment of any of the present apparatuses and methods can consistof or consist essentially of—rather thancomprise/include/contain/have—any of the described steps, elements,and/or features. Thus, in any of the claims, the term “consisting of” or“consisting essentially of” can be substituted for any of the open-endedlinking verbs recited above, in order to change the scope of a givenclaim from what it would otherwise be using the open-ended linking verb.

Details associated with the embodiments described above and others arepresented below.

BRIEF DESCRIPTION OF THE DRAWINGS

The following drawings illustrate by way of example and not limitation.For the sake of brevity and clarity, every feature of a given structureis not always labeled in every figure in which that structure appears.Identical reference numbers do not necessarily indicate an identicalstructure. Rather, the same reference number may be used to indicate asimilar feature or a feature with similar functionality, as maynon-identical reference numbers. The figures are drawn to scale (unlessotherwise noted), meaning the sizes of the depicted elements areaccurate relative to each other for at least the embodiment depicted inthe figures.

FIG. 1A depicts a perspective view of a first embodiment of the presentapparatuses having a cannula and a penetrator, with the cannula shownnext to the penetrator.

FIG. 1B depicts a cross-sectional view of the apparatus of FIG. 1A, withthe cannula shown next to the penetrator.

FIG. 1C depicts a cross-sectional view of an enlarged head of thepenetrator shown in FIG. 1A.

FIG. 1D depicts a cross-sectional view of a first end of the cannulashown in FIG. 1A.

FIG. 2A depicts a perspective view of the apparatus of FIG. 1A, with thepenetrator shown in the cannula.

FIG. 2B depicts a cross-sectional view of the apparatus of FIG. 1A, withthe penetrator shown in the cannula.

FIG. 2C depicts a cross-sectional view of a portion of the apparatus ofFIG. 1A that includes a second end of the cannula and a distal end ofthe penetrator, with the penetrator shown in the cannula.

FIG. 3 depicts a perspective view of a second embodiment of the presentapparatuses.

FIGS. 4A and 4B depict perspective view of the apparatus of FIG. 3positioned for use relative to a patient's knee, and are not drawn toscale.

FIG. 5A depicts a side view of a second embodiment of the presentpenetrators.

FIGS. 5B and 5C depict enlarged side views of a penetration portion ofthe penetrator of the penetrator of FIG. 5A.

FIG. 6 depicts a side cross-sectional view of a second embodiment of thepresent cannulas.

FIG. 7A depicts a side cross-sectional view of a third embodiment of thepresent cannulas.

FIG. 7B depicts an enlarged cross-sectional view of a distal portion ofthe cannula of FIG. 7A.

FIGS. 8A-8C depict various views of handle for use with the presentcannulas.

FIG. 9 depicts an exploded perspective view of a kit comprising anembodiment of the present apparatuses and a package for the apparatus.

FIGS. 10A-10D depict various views of another embodiment of the presentapparatuses that includes a penetrator removal tab in combination withthe penetrator of FIG. 5A and a fourth embodiment of the presentcannulas.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The term “coupled” is defined as connected, although not necessarilydirectly, and not necessarily mechanically; two items that are “coupled”may be unitary with each other. The terms “a” and “an” are defined asone or more unless this disclosure explicitly requires otherwise. Theterm “substantially” is defined as largely but not necessarily whollywhat is specified (and includes what is specified; e.g., substantially90 degrees includes 90 degrees and substantially parallel includesparallel), as understood by a person of ordinary skill in the art. Inany embodiment of the present apparatuses, kits, and methods, the term“substantially” may be substituted with “within [a percentage] of” whatis specified, where the percentage includes 0.1, 1, 5, and/or 10percent.

The terms “comprise” (and any form of comprise, such as “comprises” and“comprising”), “have” (and any form of have, such as “has” and“having”), “include” (and any form of include, such as “includes” and“including”) and “contain” (and any form of contain, such as “contains”and “containing”) are open-ended linking verbs. As a result, anapparatus or kit that “comprises,” “has,” “includes” or “contains” oneor more elements possesses those one or more elements, but is notlimited to possessing only those elements. Likewise, a method that“comprises,” “has,” “includes” or “contains” one or more steps possessesthose one or more steps, but is not limited to possessing only those oneor more steps.

Further, an apparatus, device or system that is configured in a certainway is configured in at least that way, but it can also be configured inother ways than those specifically described.

Referring now to the drawings, and more particularly to FIGS. 1A-2C,shown therein and designed by the reference numeral 10 is one embodimentof the present apparatuses for creating microfractures in bone (e.g.,subchondral bone). In the embodiment shown, apparatus 10 comprises apenetrator 14, a cannula 18, and a handle 22 coupled to cannula 18. Inother embodiments (e.g., as shown in FIG. 3), handle 22 may be omitted.In the embodiment shown, cannula 18 has a first end 26, a second end 30,and a channel 34 extending between the first end and the second end.Such first and second ends should be understood as the locations of thebeginning and end of the channel. In this embodiment, cannula 18 has aprimary portion 38 and a distal portion 42, with primary portion 38extending between first end 26 and distal portion 42 (e.g., a majorityof the length of the cannula, as in the embodiment shown), and withdistal portion 42 extending between primary portion 38 and second end30. The distal portion can be configured such that a second end of thechannel (at second end 30) is disposed at an angle relative to a firstend of the channel (at first end 26). For example, in the embodimentshown, distal portion 42 is disposed at an angle 46 relative to theprimary portion. In the embodiment shown, angle 46 is between 10 and 30degrees (e.g., 20 degrees). In other embodiments, angle 46 can be anysize that permits apparatus 10 to function as described in thisdisclosure (e.g., angle 46 can be equal to, or between any two of: 0,10, 20, 30, 40, 45, 50, and/or 60 degrees). In other embodiments, angle46 can be greater than 60 degrees (e.g., equal to, or between any twoof: 60, 70, 80, 90, and/or more degrees). As a further example, distalportion 42 can include a curved or hooked shape such that angle 46 iseffectively larger than 90 degrees (e.g., equal to, or between any twoof: 90, 120, 150, 180, and/or 180 degrees).

Primary portion 38 has a transverse dimension 50 (e.g., a diameter, inthe embodiment shown). Penetrator 14 and cannula 18 can comprise anysuitable material that permits the apparatus to function as described inthis disclosure (e.g., and permits the penetrator and the cannula to besterilized). For example, in some embodiments, penetrator 14 comprisesnickel-titanium alloy (e.g., Nitinol), and/or cannula 18 comprisesmetal, such as stainless steel (e.g., a surgical stainless steel).Embodiments of the present cannulas are rigid and configured not to flexor bend during use. In other embodiments, penetrator 14 can comprise abiocompatible metal such as stainless steel (e.g., 316L stainlesssteel).

In the embodiment shown, penetrator 14 has a proximal end 54, anenlarged head 58 adjacent proximal end 54, a primary portion 62, adistal end 66 (e.g., pointed distal end 66, as shown), and a penetrationportion 70 adjacent distal end 66. In this embodiment, penetrationportion 70 has a length 74 that is a minority of the length ofpenetrator 14 between proximal end 54 and distal end 66. In someembodiments, penetrator 14 has a transverse dimension of less than 1.2mm (e.g., between 1 mm and 1.1 mm; less than 1.1 mm, less than 1.05 mm,less than 1 mm; less than, or between any two of, 0.5, 0.6, 0.7, 0.8,0.9, and/or 1 mm). For example, in the embodiment shown, penetrationportion 70 has a circular cross-section with a diameter 78 of between0.7 and 0.8 mm (e.g., 0.78 mm). In some embodiments, penetration portion70 has a circular cross-section with a diameter of between 1 and 1.1 mm(e.g., 1.04 mm). Penetrator 14 is configured to be disposed in channel34 of cannula 18 such that penetrator 14 is movable between a (1)retracted position (e.g., in which distal end 66 of the penetrator doesnot extend beyond second end 30 of the cannula) and (2) an extendedposition in which distal end 66 of the penetrator extends beyond secondend 30 of the cannula by a penetration distance 82. In some embodiments,penetration distance 82 is at least (e.g., greater than) 5 mm (e.g., 7mm, 8 mm, 8-10 mm, more than 10 mm) and/or at least (e.g., greater than)5 times (e.g., greater than, or between any two of: 6, 7, 8, 9, 10, ormore times) a transverse dimension (e.g., diameter) of penetrator 14(e.g., diameter 78 of penetration portion 70). For example, in theembodiment shown, penetration distance 82 is between 8 mm and 10 mm(e.g., 10 mm), which is greater than 12 times diameter 78. In theembodiment shown, diameter 50 of primary portion 38 is larger thandiameter 78 of penetration portion 70. In some embodiments, diameter 50is also less than 1.2 mm (e.g., between 1 mm and 1.1 mm, less than 1.1mm, less than 1.05 mm). In some embodiments, diameter 50 issubstantially equal to diameter 78. In some embodiments, penetrator 14comprises a central wire defining diameter 78 that is encircled orencased by an outer tubing (e.g., metallic tubing, plastic shrink wrap,and/or the like along the length of primary portion 62 to definetransverse dimension 50.

In some embodiments, a coating is disposed on at least penetrationportion 70 of penetrator 14 (the coating may also be disposed on primaryportion 62 of the penetrator). In some embodiments, the coating ishydrophilic. Examples of hydrophilic coatings include Hydro-Silkcoatings available from TUA Systems of Florida (U.S.A.). In someembodiments, the coating comprises silver ions. In some embodiments, thecoating comprises one or more active ingredients configured to elicit orstimulate a biological response in (e.g., bone or cartilage) tissue,such as, for example, growth factor(s), anticoagulant(s), protein(s),and/or the like. Such coatings can be applied as known in the art forthe materials used in particular embodiments.

In the embodiment shown, cannula 18 is configured to provide lateralsupport for penetrator 14, such as to prevent the penetrator frombending or buckling while being driven into the hard subchondral bone.For example, in the embodiment shown, diameter 50 of primary portion 62of the penetrator is nearly as large as (e.g., greater than, or betweenany two of: 95, 96, 97, 98, 99, and or 100 percent of) the diameter ofchannel 34, and diameter 78 of penetration portion 70 is greater than75% (e.g., greater than, or between any two of: 75, 80, 85, 90, 95,and/or 100 percent of) the diameter of channel 34 (e.g., the diameter ofchannel 34 adjacent second end 30 of the cannula). In some embodiments,penetrator 14 is substantially straight prior to being disposed inchannel 34 of cannula 18, such that inserting the penetrator into thecannula causes the penetration portion 70 of the penetrator to be angledrelative to primary portion 62. In some such embodiments, penetrator 14may be resilient enough to (e.g., at least partially) return to itsstraight shape after removal from the cannula.

In some embodiments, penetrator 14 is configured to be moved or advanced(e.g., substantially without rotation of the penetrator) from theretracted position to the extended position (FIG. 2B) to form amicrofracture in subchondral bone (e.g., in a patient's knee or shoulderjoint), the microfracture having a depth of at least (e.g., more than) 5mm (e.g., 7 mm, 8 mm, 8-10 mm, more than 10 mm) and/or at least (e.g.,greater than) 5 times (e.g., greater than, or between any two of: 6, 7,8, 9, 10, or more times) a transverse dimension (e.g., diameter) ofpenetrator 14 (e.g., diameter 78 of penetration portion 70). Forexample, in the embodiment shown, penetrator 14 is configured to bemoved or advanced (e.g., substantially without rotation of thepenetrator, which includes no rotation up to rotation of less than onefull revolution clockwise and/or counterclockwise from the position atwhich distal end 66 of the penetrator first contacts the bone) from theretracted position to the extended position (FIG. 2B) to form amicrofracture in subchondral bone (e.g., in a patient's knee or shoulderjoint), the microfracture having a depth of between 8 mm and 10 mm(e.g., 10 mm), which is greater than 12 times diameter 78. In theembodiment shown, penetrator 14 is configured to be moved or advancedmanually to the extended position. As used in this disclosure, moved oradvanced “manually” means without the assistance of an external energysource other than that provided by a user. For example, if thepenetrator is moved or advanced with a battery-powered or spring-drivendriver, it would not be “manually.” Conversely, the penetrator would bemoved or advanced “manually” if a mallet, hammer, or other tool is swungby a user (e.g., in the user's hand) to impact first end 26 of thepenetrator. In some embodiments, the present apparatuses are configuredsuch that the penetrator can (but need not) be rotated as it is advancedor moved from the retracted position to the advanced position. Forexample, a portion of the penetrator (e.g., enlarged head 58) can bedisposed in the chuck of a drill such that the drill can rotate thepenetrator. In such embodiments, the penetrator may (but need not) besubstantially straight or axial (without bends) along its entire length(e.g., prior to being disposed in a cannula with an angled distalportion).

In the embodiment shown, penetration distance 82 (and the depth of themicrofracture the apparatus is configured to create) is limited byenlarged head 58 contacting the cannula (e.g., penetration distance ismaximized when enlarged head 58 contacts the cannula, as shown in FIG.2B). For example, in the embodiment shown, cannula 18 includes arecessed portion 86 and a shelf 90. As shown, recessed portion 86extends from first end 26 toward second end 30 (inwardly), and shelf 90is disposed between recessed portion 86 and second end 30 such thatpenetration distance 82 is limited by enlarged head 58 contacting shelf90. For example, in the embodiment shown, enlarged head 58 has acylindrical (e.g., circular cylindrical, as shown) with a first end 94and a second end 98, and is configured such that second end 98 contactsshelf 90 when the penetrator is in the extended position relative to thecannula (FIG. 2B). In some embodiments, recessed portion 86 can beconfigured to maintain the orientation or alignment of enlarged head 58as the penetrator is moved or advanced from the retracted position tothe extended position. For example, in some embodiments, recessedportion 58 has a depth 102 that is at least as large as (e.g., isgreater than, or between any two of: 100, 110, 120, 130, 140, 150, ormore percent of) penetration distance 82 (e.g., such that enlarged head58 is at least partially within recessed portion 86 when distal end 66extends beyond second end 30 of the cannula), and/or enlarged head 58has a transverse dimension (e.g., diameter) that is at least 90% (e.g.,greater than, or between any two of: 90, 92, 94, 96, 98, and/or 100percent) of a corresponding transverse dimension of recessed portion 86(e.g., such that cannula 18 limits tilting of enlarged head 58 relativeto cannula 14, and/or limits misalignment of enlarged head 58 relativeto primary portion 62 of the penetrator).

For example, in the embodiment shown, depth 102 of recessed portion 58is between 175% and 250% (e.g., between 200% and 225%) of penetrationdistance 82. In this embodiment, enlarged head 58 and recessed portion86 each has a circular cross section, and enlarged head 58 has adiameter 106 that is between 90% and 100% (e.g., between 95% and 100%)of diameter 110 of recessed portion 86. In some embodiments, a length114 of enlarged head 58 is at least 150% (e.g., at least, or between anytwo of: 150, 175, 200, 225, 250, 300, or more percent) of penetrationdistance 82. For example, in the embodiment shown, length 114 is over300% of penetration distance 82, such that a portion of enlarged head 58that is at least as long as penetration distance 82 is disposed inrecessed portion 86 when distal end 66 of the penetrator is even withsecond end 30 of the cannula (and the orientation of enlarged head 58relative to cannula 18 is thereby maintained). In some embodiments,enlarged head 58 has an elongated shape such that length 114 is greaterthan (e.g., greater than, or between any two of: 2, 3, 4, 6, 8, or moretimes) diameter 106. For example, in the embodiment shown, length 114 isbetween 8 and 12 times diameter 106.

FIG. 3 depicts a second embodiment 10 a of the present apparatuses.Apparatus 10 a is substantially similar to apparatus 10, with theexception that apparatus 10 a does not include a handle (e.g., handle22).

Embodiments of the present kits can comprise one or more of the presentcannulas (e.g., cannula 14) and a reusable tray or other container in apackage (e.g., a sealed pouch or the like), where both the cannula(s)and the tray are or can be sterilized (and can be re-sterilized inadvance of being re-used). Both the tray and the package may berectangular in shape. In addition, some embodiments of the present kitscan also include two or more penetrators configured to create differentmicrofractures. For example, some embodiments of the present kitscomprise one or more of the present cannulas, a sterilizable tray, afirst penetrator configured to have a penetration distance of between 5mm and 8 mm when used in combination with the cannula, and a secondpenetrator configured to have a penetration distance greater than 8 mmwhen used in combination with the cannula. More specifically, someembodiments of the present kits may include a package (e.g., a box or aflexible package) that comprises sterilized versions of these items.Other embodiments of the present kits comprise one or more of thepresent penetrators (e.g., a single penetrator or two penetrators havingdifferent penetration depths, different tip diameters, different tipshapes, and/or the like) that are sterile and disposed in a package.Embodiments of the present kits may also include, in more specificembodiments, instructions for use, which instructions may be inside thepackage (e.g., as an insert) or outside the package (such as a stickeron the package).

FIGS. 4A and 4B depict an example of the present methods (e.g., usingembodiment 10 a of the present apparatuses). Some embodiments of thepresent methods comprise: disposing an embodiment of the presentmicrofracture apparatuses (e.g., 10, 10 a) adjacent to subchondral boneof a patient (e.g., in the knee, shoulder, or other joint). For example,in the embodiment shown, apparatus 10 a is disposed adjacent tosubchondral bone of articular surface 150 in a patient's knee 154 (e.g.,with second end 30 of cannula 18 in contact with the subchondral bone,as shown). Some embodiments further comprise moving or advancingpenetrator 14 relative to cannula 18 (e.g., from FIG. 4A to FIG. 4B)until distal end 66 of the penetrator extends into the subchondral bone(as in FIG. 4B) to form a microfracture having a depth of at least 5 mm.For example, in the embodiment shown, penetrator 18 is manually advancedsubstantially without rotation of the penetrator by striking orimpacting proximal end 54 of the penetrator with a mallet 158 untildistal end 66 extends into the subchondral bone by a distance of, andforms a microfracture 162 having a depth of, 10 mm. In the embodimentshown, the position of second end 30 of the cannula relative to thesubchondral bone remains substantially constant while advancing thepenetrator into the bone. In some embodiments of the present methods,the apparatus is repeatedly disposed adjacent the bone (e.g., withsecond end 30 of the cannula in contact with the subchondral bone and/orin contact with cartilage, such as, for example, cartilage around theperimeter of a lesion), and the penetrator is repeatedly advanced intothe subchondral bone to form a plurality of microfractures (e.g., havingsubstantially the same depths). In some embodiments, the present methodscan be performed on and/or in the surfaces of other joints, such as, forexample, the shoulder, the ankle, the hip, and/or the patellofemoraljoint within the knee.

Referring now to FIGS. 5A-5C, a second embodiment 14 a of the presentpenetrators is shown. Penetrator 14 a is similar in many respects topenetrator 14. For example, penetrator 14 a has a proximal end 54, aprimary portion 62, a distal end 66 (e.g., pointed distal end 66, asshown), and a penetration portion 70 a adjacent distal end 66. While notshown in FIG. 5A, penetrator 14 a can also include an enlarged head(similar to enlarged head 58 of penetrator 14). In this embodiment,penetration portion 70 a has a length 74 a that is a minority of thelength of penetrator 14 a between proximal end 54 and distal end 66.Similarly, in some embodiments, penetrator 14 a has a transversedimension of less than 1.2 mm (e.g., between 1 mm and 1.1 mm; less than1.1 mm, less than 1.05 mm, less than 1 mm; less than, or between any twoof, 0.5, 0.6, 0.7, 0.8, 0.9, and/or 1 mm). For example, in theembodiment shown, penetration portion 70 a has a circular cross-sectionwith a diameter 78 a of between 1 and 1.2 mm (e.g., 1.04 mm). As withpenetrator 14, penetrator 14 a is configured to be disposed in channel34 of cannula 18 such that penetrator 14 is movable between a (1)retracted position (e.g., in which distal end 66 of the penetrator doesnot extend beyond second end 30 of the cannula) and (2) an extendedposition in which distal end 66 of the penetrator extends beyond secondend 30 of the cannula by a penetration distance 82, which may, forexample, be at least (e.g., greater than) 5 mm (e.g., 7 mm, 8 mm, 8-10mm, more than 10 mm) and/or at least (e.g., greater than) 5 times (e.g.,greater than, or between any two of: 6, 7, 8, 9, 10, or more times) atransverse dimension (e.g., diameter) of penetrator 14 (e.g., diameter78 a of penetration portion 70).

For example, in the embodiment shown, penetration distance 82 is between8 mm and 10 mm (e.g., 10 mm), which is greater than 7 times diameter 78a. In some embodiments, the length of the penetration portion is greaterthan a penetration distance 82 for which the penetrator is designed. Forexample, in the embodiment shown, length 74 a is greater than thepenetration distance 82 (e.g., and greater than the sum of penetrationdistance 82 and the length of distal portion 42 of cannula 14 and/orcannula 14 a). In the embodiment shown, diameter 50 of primary portion38 is larger than diameter 78 a of penetration portion 70 a, and/orequal to or greater than 1.2 mm (e.g., substantially equal to 1.27 mm)and/or less than 2.0 mm. In some embodiments, diameter 50 is also lessthan 1.2 mm (e.g., between 1 mm and 1.1 mm, less than 1.1 mm, less than1.05 mm). In some embodiments, diameter 50 is substantially equal todiameter 78.

In some embodiments, penetrator 14 comprises a central wire definingtransverse dimension 78 a that is encircled or encased by an outertubing (e.g., metallic tubing, plastic shrink wrap, and/or the likealong the length of primary portion 62 a to define transverse dimension50 a.

As shown in FIGS. 5B and 5C, however, penetration portion 70 a differsfrom penetration portion 70 in that penetration portion 70 a isconfigured to reduce (e.g., relative to that of penetration portion 70)the force required to insert distal end 66 into a bone, and to reduce(e.g., relative to that of penetration portion 70) the force required toremove distal end 66 from the bone. For example, in the embodimentshown, penetration portion 70 includes a narrow portion 200 betweendistal end 66 and primary portion 62, with narrow portion 200 beingnarrower in at least one transverse dimension than primary portion 62.In this embodiment, narrow portion 200 is configured to reduce thesurface area of penetration portion 70 a that is in contact with bonewhen the penetration portion is driven into a bone. For example, theenlarged part of penetration portion 70 a adjacent distal end 66 (andcorresponding to first transverse dimension 78 a) creates a path throughthe bone during insertion that is larger than narrow portion 200, suchthat at least a part of narrow portion 200 is not (at least initially)in contact with the bone. Even if penetration portion 70 a remains inthe bone for a sufficient time for the bone to rebound towards narrowportion 200, the reduced transverse dimension of narrow portion 200 mayreduce the interface pressure between the penetrator and the reboundedbone material. This reduced contact and/or reduced interface pressurecan reduce the force required to remove distal end 66 from the bone(e.g., relative to the force required to remove from the same type ofbone penetration portion 70 of penetrator 14, which has a circularcylindrical shape with constant diameter and cross-section along thelength of penetration portion 70—i.e., does not include narrow portion200).

For example, in the embodiment shown, transverse dimension 78 a is afirst transverse dimension in the penetration portion, and a secondtransverse dimension 204 that is smaller than first transverse dimension78 a is between primary portion 62 and first transverse dimension 78 a(in penetration portion 70 a, as shown). In some embodiments, secondtransverse dimension 204 is substantially constant along part of length74. For example, in the embodiment shown, narrow portion 200 has alength 208 along which second transverse dimension 204 is substantiallyconstant. In the embodiment shown, length 208 is between 20 percent and35 percent of length 74 a of penetration portion 70 a. In otherembodiments, length 208 can be any suitable fraction or percentage oflength 74 a (e.g., less than any one of, or between any two of, 5, 10,15, 20, 25, 30, 35, 40, 45, and/or 50 percent). In some embodiments,first transverse dimension 78 a is adjacent distal end 66 (i.e., closerto distal end 66 than to primary portion 62). For example, in theembodiment shown, the distance between distal end 66 and narrow portion200 is less than length 208 of the narrow portion. In other embodiments,narrow portion can be disposed at any suitable position along the lengthof penetration portion 70 a. In the embodiment shown, penetrationportion 70 a further includes a third transverse dimension 212 betweennarrow portion 200 and primary portion 62. In this embodiment, thirdtransverse dimension 212 is substantially equal to first transversedimension 78 a, but may differ in other embodiments. In the embodimentshown, third transverse dimension is substantially constant along aproximal segment 214 of penetration portion 70 a.

In some embodiments, penetrator 14 a has a first cross-sectional shapeand/or area at first transverse dimension 78 a, a second cross-sectionalshape and/or area at second transverse dimension 204, and the firstcross-sectional shape and/or area is larger than (e.g., and, as shown,concentric to) the second cross-sectional shape and/or area. Forexample, in the embodiment shown, penetrator 14 a has a first circularcross section at first transverse dimension 78 a, and a second circularcross section at second transverse dimension 204 (e.g., with the firstcircular cross-section being substantially concentric with the secondcircular cross-section, as shown). In this embodiment, penetrator 14 aalso has a circular cross-section at third transverse dimension 212. Inother embodiments, the penetrator, the penetration portion, and/or thenarrow portion can have any suitable cross-sectional shapes (e.g.,circle, square, triangular, rectangular, star, and/or the like), whethersimilar or dissimilar (e.g., the cross-sectional shape of the narrowportion may differ from the cross-sectional shape of the remainder ofthe penetration portion), such that the cross-sectional shape of thesurface of area of the narrow portion that contacts bone duringinsertion is reduced. For example, in some embodiments, the penetrationportion can have a circular cross-section and the narrow portion canhave a rectangular cross-section. In other embodiments, narrow portion200 may be fluted.

In the embodiment shown, penetration portion 70 a also differs frompenetration portion 70 in that distal end 66 is configured to reduce(e.g., relative to that of penetration portion 70) the force required toinsert distal end 66 into a bone, and to reduce (e.g., relative to thatof penetration portion 70) the force required to remove distal end 66from the bone. For example, in the embodiment shown, distal end 66includes a pointed tip 216 with a cross-sectional shape defined by a tipangle 220 of 60 degrees or greater (e.g., substantially equal to 60degrees, as shown). For example, in the embodiment shown, pointed tip216 has a conical shape having a cross-sectional shape that is bisectedby a central longitudinal axis 224 of penetration portion 70 a. In otherembodiments, pointed tip 216 can have any suitable shape (e.g., atriangular or rectangular pyramid). In some embodiments, tip angle 220is greater than 60 degrees, greater than 90 degrees, and/or greater than120 degrees (e.g., equal to 180 degrees, or substantially perpendicularto a longitudinal axis of an adjacent portion of penetration portion 70a). For example, a tip angle 220 of 60 degrees, as shown, reduces thelength of the cone that defines pointed tip relative to the 30 degreetip angle of penetrator 14, and thereby reduces the surface area of thecone that is available to contact bone during insertion and removal.Likewise, further increases in tip angle 220 will further reduce thesurface area of a conical pointed that is available to contact bone. Inthe embodiment shown, penetration portion 70 a further includes a firstradiused portion 228 (which may instead be linearly tapered) betweenpointed tip 216 (and first transverse dimension 78 a) and narrow portion200, and a second tapered portion 232 (which may instead be radiused)between proximal segment 214 and narrow portion 200, to reducelikelihood of the transitions in transverse dimension resulting inpoints along penetration portion 70 a that might otherwise catch orresist insertion or removal of distal end 66 into or from bone. In otherembodiments, the tip can be rounded and/or can be defined by a single(e.g., planar) facet extending across the entire cross-section of thepenetration portion.

In the embodiment shown, penetrator 14 a is substantially straight priorto being disposed in channel 34 of cannula 18 or cannula 18 b, such thatinserting the penetrator into the cannula causes the penetration portion70 a of the penetrator to bend within channel 34 (between primaryportion 38 or 38 a and distal portion 42 or 42 a). In some suchembodiments, penetrator 14 a may be resilient enough to (e.g., at leastpartially) return to its straight shape after removal from the cannula.

FIG. 6 depicts a side cross-sectional view of a second embodiment 18 aof the present cannulas. Cannula 18 a is similar in many respects tocannula 18. For example, cannula 18 a has a first end 26, a second end30, and a channel 34 extending between the first end and the second end.Such first and second ends should be understood as the locations of thebeginning and end of the channel. In this embodiment, cannula 18 has aprimary portion 38 a and a distal portion 42 a, with primary portion 38a extending between first end 26 and distal portion 42 a (e.g., amajority of the length of the cannula, as in the embodiment shown), andwith distal portion 42 a extending between primary portion 38 and secondend 30. In the embodiment shown, cannula 18 a differs from cannula 18 inthat in cannula 18 a, distal portion 42 a is not angled relative toprimary portion 38 a (distal portion 42 a and primary portion 38 a sharea common central longitudinal axis). Primary portion 38 a has atransverse dimension 300 (e.g., a diameter, in the embodiment shown). Inthe embodiment shown, distal portion 42 a is tapered between primaryportion 38 a and second end 30, as shown. In this embodiment distalportion 42 a has a length 304 that is less than a length 308 of cannula18 a (e.g., less than 20 percent of length 308). In other embodiments,the relative lengths of primary portion 38 a and distal portion 42 a canbe any suitable sizes for various procedures and/or for patients ofvarious ages and/or sizes. In some embodiments of the present methods,cannula 18 a is bent to form a cannula with an angled distal portion, asdescribed below.

Referring now to FIGS. 7A and 7B, side cross-sectional views are shownof a third embodiment 18 b of the present cannulas. Cannula 18 b issubstantially similar to cannula 18, with the exception that angle 46 bis substantially equal to 15 degrees. In some embodiments, angle 46 bcan be between 5 degrees and 20 degrees (e.g., substantially equal toeither of, or between, 10 degrees and 15 degrees). In other embodiments,angle 46 b can be greater than 60 degrees (e.g., equal to, or betweenany two of: 60, 70, 80, 90, and/or more degrees). As a further example,distal portion 42 b can include a curved or hooked shape such that angle46 b is effectively larger than 90 degrees (e.g., equal to, or betweenany two of: 90, 120, 150, 180, and/or 180 degrees).

FIGS. 7A and 7B also include dimensions (in inches) for at least oneexemplary embodiment of the present cannulas. Further, the differencebetween cannula 18 a of FIG. 6 and cannula 18 b of FIGS. 7A and 7Billustrate an embodiment of the present methods. In particular, someembodiments of the present methods (e.g., of making the presentcannulas) comprise forming cannula 18 b by bending (e.g., with a jig orthe like) cannula 18 a to angle 46.

FIGS. 8A-8C depict various views of handle 22. FIG. 8B includesdimensions (in inches) for at least one exemplary embodiment of thepresent handles. As shown, handle 22 comprises a central longitudinalpassage 312 configured to receive part of a primary portion (e.g., 38,38 a) of a cannula (e.g., 18, 18 a, 18 b), such as, for example, via apress fit or the like.

FIG. 9 depicts an exploded perspective view of a kit 400 comprising anembodiment 10 of the present apparatuses and a package 404 for theapparatus. In the embodiment shown, package 404 comprises a lower panel408, a foam or other (e.g., molded plastic) receptacle 412 configured toreceive apparatus 10 (including penetrator 14 and cannula 18), and anupper panel 416. In the embodiment shown, kit 400 also includesinstructions 420 and a box 424. As indicated by the arrangement ofpanels 408 and 416, receptacle 412, and instructions 420, thesecomponents fit into box 424. In some embodiments, such as the one shown,cannula 18 (including handle 22) and/or penetrator 14 are sterile and/orsealed in plastic independently of receptacle 412.

FIGS. 10A-10D depict various views of another embodiment 10 b of thepresent apparatuses that includes a penetrator removal tab 500 incombination with a penetrator 14 b and a fourth embodiment 18 c of thepresent cannulas. In the embodiment shown, tab 500 comprises a body 504with a first end 508, a second end 512, a distal side 516, and aproximal side 520. In the embodiment shown, distal side 516 isconfigured to face toward second end 30 of cannula 18 c, and comprises aprotrusion 524 configured to contact handle 22 to act as a fulcrumduring use, as described in more detail below. In the embodiment shown,distal side 520 includes a plurality of grooves 528 to contact andresist slippage of a user's thumb during use. In other embodiments,grooves 528 may be omitted and/or substituted with a different type oftexture. As shown in FIGS. 10C and 10D, body 504 has a curved or arcuateshape such that distal side 516 is concave and proximal side 520 isconvex.

In the embodiment shown, body 504 includes an elongated opening 532 thatis closer to first end 508 than to second end 512, and that isconfigured to receive enlarged head 58 of penetrator 14 a as shown inFIGS. 10B and 10C. For example, in some embodiments, opening 516 canhave a width (smaller transverse dimension) that is between 100% and150% (e.g., between any two of: 100%, 110%, 120%, 130%, 140%, and 150%)of a corresponding transverse dimension (e.g., diameter 106) of enlargedhead 58, and/or can have a height (larger transverse dimension) that isbetween 150% and 250% (e.g., between any two of: 150%, 175%, 200%, 225%,and 250%) of a corresponding transverse dimension (e.g., diameter 106)of enlarged head 58. The elongated shape of opening 532 permits tab 500to pivot relative to enlarged head 58 (and overall penetrator 14 b) toapply an axial removal force to penetrator 14 b while minimizing anylateral force that might otherwise deflect and/or impede movement of thepenetrator.

As shown, proximal side 520 of body 504 also includes a recess 536configured to at least partially receive FIG. 10C) a correspondingflange 542 that is coupled to (e.g., unitary with) enlarged head 58. Forexample, in the embodiment shown, flange 542 is configured to bedisposed over and coupled in fixed relation to proximal end 54 andenlarged head 58 of penetrator 14 b. In his embodiment, flange 542includes a neck 546 configured to be crimped and/or adhered via adhesiveto enlarged head 58. In other embodiments, flange 542 may be unitarywith enlarged head. As shown, flange 542 has a transverse dimension(e.g., diameter) that is larger than a corresponding transversedimension (e.g., diameter) of opening 504 but smaller than acorresponding transverse dimension of recess 536. In some embodiments,enlarged head 58 is omitted and flange 542 and opening 528 (e.g., andrecess 532) also limits the maximum penetration distance 82.

In use, a penetrator 14 b (e.g., having flange 542 coupled to enlargedhead 58) can be inserted through opening 528 and into cannula 18 c suchthat tab 500 is disposed between flange 542 and handle 22 a of cannula18 c. Second end 30 of cannula 18 c can then be disposed in a desiredlocation relative to a bone, and penetrator 14 b can be impacted todrive distal end 66 of the penetrator into the bone. With distal end 66disposed in the bone, a user can apply a force to proximal side 520 oftab 500 in direction 550 (toward second end 30 of cannula 18 c) to causetab 500 to pivot around protrusion 524 and apply a force to flange 542to retract the penetrator in direction 524. In the embodiment shown,protrusion 524 is sized such that a second part of tab 500 (504) willalso contact handle 22 a at point 558 (such that protrusion once thepenetrator is retracted by a distance about equal to or just larger thanthe maximum penetration distance (e.g., 82 of FIG. 2C) of thepenetrator/cannula combination to prevent protrusion 524 from furtheracting as a fulcrum for tab 500. For example, limiting the retractiondistance (e.g., to between 100% and 120% of maximum penetration distance82) in this way can minimize the lateral force applied to enlarged head58 during retraction of the penetrator and can facilitate reinsertion ofthe penetrator in a new location by minimizing the distance thepenetrator must be advanced to bring its distal end (66) into initialcontact with the bone at the new location.

In the embodiment shown, handle 22 a is substantially similar to handle22 with the exception that handle 22 a includes a protrusion 562 that isaligned with distal portion 42 of cannula 18 c. For example, in thisembodiment, primary portion 38 of cannula 18 c, distal portion 42 ofcannula 18 c, and protrusion 562 of handle 22 d are each bisected by asingle common plane. Protrusion 562 thus provides an indicator for auser of the orientation of distal portion 42 (e.g., even when distalportion 42 is disposed within a patient and out of the user's sight). Inother embodiments, any suitable indicator may be used (e.g., adepression instead of a prorusion, an arrow printed or painted on handle22, and/or the like).

The above specification and examples provide a complete description ofthe structure and use of exemplary embodiments. Although certainembodiments have been described above with a certain degree ofparticularity, or with reference to one or more individual embodiments,those skilled in the art could make numerous alterations to thedisclosed embodiments without departing from the scope of thisinvention. As such, the various illustrative embodiments of the presentdevices are not intended to be limited to the particular formsdisclosed. Rather, they include all modifications and alternativesfalling within the scope of the claims, and embodiments other than theone shown may include some or all of the features of the depictedembodiment. For example, penetrator 18 and/or channel 34 can have anysuitable cross-sectional shape (e.g., triangular, square, rectangular,and/or the like) that permits the present apparatuses and methods tofunction as described in this disclosure. For example, components may becombined as a unitary structure, and/or connections may be substituted.Further, where appropriate, aspects of any of the examples describedabove may be combined with aspects of any of the other examplesdescribed to form further examples having comparable or differentproperties and addressing the same or different problems. Similarly, itwill be understood that the benefits and advantages described above mayrelate to one embodiment or may relate to several embodiments.

The claims are not intended to include, and should not be interpreted toinclude, means-plus- or step-plus-function limitations, unless such alimitation is explicitly recited in a given claim using the phrase(s)“means for” or “step for,” respectively.

1-20. (canceled)
 21. An apparatus comprising: a cannula having a firstend, a second end, and a channel extending between the first end and thesecond end; a penetrator having a distal end and a first transversedimension of less than 1.2 millimeters (mm), the penetrator configuredto be disposed in the channel of the cannula such that the penetrator ismovable between a retracted position and an extended position in whichthe distal end extends beyond the second end of the cannula by apenetration distance of at least 5 mm; a penetrator removal tab coupledto the penetrator and configured to retract the penetrator relative tothe cannula; and an enlarged head coupled to the penetrator; where thepenetrator is configured to be moved from the retracted position to theextended position substantially without rotation of the penetrator toform a microfracture having a depth of at least 5 mm; and where: thecannula includes a handle, the penetrator removal tab includes anopening that has at least one transverse dimension that is smaller thana transverse dimension of the enlarged head, and the penetrator removaltab is configured to be disposed between the handle and the enlargedhead with the penetrator extending through the opening.
 22. Theapparatus of claim 21, where the penetrator removal tab includes aprotrusion configured to extend toward the second end of the cannula andcontact the handle to act as a fulcrum for pivoting the penetratorremoval tab.
 23. The apparatus of claim 22, where the penetrator isconfigured to be manually moved from the retracted position to theextended position.
 24. An apparatus comprising: a cannula having a firstend, a second end, and a channel extending between the first end and thesecond end; a penetrator having a distal end and a first transversedimension of less than 1.2 millimeters (mm), the penetrator configuredto be disposed in the channel of the cannula such that the penetrator ismovable between a retracted position and an extended position in whichthe distal end extends beyond the second end of the cannula by apenetration distance of at least 5 mm; a penetrator removal tab coupledto the penetrator and configured to retract the penetrator relative tothe cannula; and an enlarged head coupled to the penetrator; where thepenetrator is configured to be moved from the retracted position to theextended position substantially without rotation of the penetrator toform a microfracture having a depth of at least 5 mm; and where: thecannula includes a handle, the penetrator removal tab includes anopening that has at least one transverse dimension that is smaller thana transverse dimension of the enlarged head, and the penetrator removaltab is configured to be disposed between the handle and the enlargedhead with the penetrator extending through the opening.
 25. Theapparatus of claim 24, where the penetrator removal tab includes aprotrusion configured to extend toward the second end of the cannula andcontact the handle to act as a fulcrum for pivoting the penetratorremoval tab.
 26. The apparatus of claim 25, where the penetrator isconfigured to be manually moved from the retracted position to theextended position.
 27. An apparatus comprising: a cannula having a firstend, a second end, and a channel extending between the first end and thesecond end; a penetrator having a distal end and a first transversedimension, the penetrator configured to be disposed in the channel ofthe cannula such that the penetrator is movable between a retractedposition and an extended position in which the distal end extends beyondthe second end of the cannula by a penetration distance that is at least5 times greater than the first transverse dimension of the penetrator; apenetrator removal tab coupled to the penetrator and configured toretract the penetrator relative to the cannula; and an enlarged headcoupled to the penetrator; where the penetrator is configured to bemoved from the retracted position to the extended position substantiallywithout rotation of the penetrator to form a microfracture having adepth that is at least 5 times greater than the first transversedimension of the penetrator; and where: the cannula includes a handle,the penetrator removal tab includes an opening that has at least onetransverse dimension that is smaller than a transverse dimension of theenlarged head, and the penetrator removal tab is configured to bedisposed between the handle and the enlarged head with the penetratorextending through the opening.
 28. The apparatus of claim 27, where thepenetrator removal tab includes a protrusion configured to extend towardthe second end of the cannula and contact the handle to act as a fulcrumfor pivoting the penetrator removal tab.
 29. The apparatus of claim 27,where the first transverse dimension of the penetrator is less than 1.2millimeters (mm).
 30. The apparatus of claim 29, where the penetrator isconfigured to be manually moved from the retracted position to theextended position.
 31. The apparatus of claim 29, where the penetrationdistance is limited by the enlarged head contacting the penetratorremoval tab and the penetrator removal tab contacting the cannula or thehandle.
 32. The apparatus of claim 31, where the cannula includes arecessed portion and a shelf, the recessed portion extending from thefirst end of the cannula toward the second end of the cannula, the shelfdisposed between the recessed portion and the second end of the cannulasuch that the penetration distance is limited by the enlarged headcontacting the shelf.
 33. The apparatus of claim 29, where a coating isdisposed on at least the penetration portion of the penetrator.
 34. Theapparatus of claim 29, where the penetrator includes a primary portionand a penetration portion disposed between the primary portion and thedistal end, the first transverse dimension is in the penetrationportion, and a second transverse dimension is between the firsttransverse dimension and the primary portion.
 35. The apparatus of claim34, where the second transverse dimension is smaller than the firsttransverse dimension.
 36. The apparatus of claim 35, where the firsttransverse dimension is closer to the distal end than to the primaryportion.
 37. The apparatus of claim 29, where the distal end includes apointed tip with a cross-sectional shape defined by a tip angle of 60degrees or greater.
 38. The apparatus of claim 37, where the tip angleis greater than 90 degrees.
 39. The apparatus of claim 38, where the tipangle is greater than 120 degrees.
 40. The apparatus claim 29, where thesecond end of the cannula is angled relative to the first end of thecannula, and the handle has an indicator indicative of the position ofthe second end of the cannula.